ABSTRACTObjective: The purpose of this study was to evaluate cephalometrically the changes in vertical and sagittal maxillomandibular relationship of a patient who had been wearing complete dentures for an extensive period. Material and methods: The patient selected for this study was a 68 years old woman who had been wearing complete dentures for 8 years. She had two prosthetic rehabilitations during this period of time, the first between 60 and 63 years, and the second between 63 and 68 years. The present rehabilitation had an overvalued occlusal vertical dimension and the patient complained of pain, discomfort, clicks, headache and weary of the masticatory muscles. New prostheses were fabricated by our conventional method and the patient was evaluated cephalometrically before and after the new prostheses. Results: After the placement of the new dentures, the vertical dimension was decreased, as shown by all the cephalometric measurements used in our article and the patient became comfortable with her prostheses. Conclusions: The severe overestimated occlusal vertical dimension was corrected by a newly fabricated denture; the cephalometric analysis was used to verify the results of this prosthetic rehabilitation.

INTRODUCTION

Cephalometric analysis has served for many years as a valuable adjunct to dental research and diagnosis. In the beginning, its clinical application has been directed largely toward orthodontics; later, some authors took it over in the prosthetic rehabilitation.1-7
Monteith used cephalometry to determine the angulation of the occlusal plane in edentulous patients, in this way reestablishing the spatial position of lost teeth (1985, 1986).4,7 He reconstructed the orientation of the occlusal plane by measuring the PoNANS angle (the angle between the cephalometric points porion, nasion and anterior nasal spine) cephalometrically; initially, he had proved the connection between this angle and the angle of the occlusal plane relative to the Frankfurt Horizontal plane.1,4-8
A few years later, Tallgren et al (1991) used it to study the soft tissue profile of the patients during a two-year period of complete denture use.9 In the most recent studies, attempts have been made to use cephalometry as a diagnostic tool in prosthodontics to evaluate the results of prosthodontic rehabilitation.1-3

MATERIALS AND METHODS

In this specific case, the cephalometric analysis has been used to evaluate the changes in vertical and sagittal maxillomandibular relationships of a 68 years old woman patient who had been wearing complete dentures for 8 years. She had two prosthetic rehabilitations during this period of time, the first between 60 and 63 years, and the second between 63 and 68 years. The purpose was to verify objectively the results of the new prosthetic construction, the third couple of complete dentures. The present rehabilitation had a overevalued occlusal vertical dimension and the patient complained of pain, discomfort, clicks, headache and weary of the masticatory muscles. (Fig. 1) The new prostheses were fabricated by the conventional method used in the clinic of the Department of Prosthodontics, Faculty of Dentistry, Carol Davila University of Medicine and Pharmacy and the patient was evaluated cephalometrically before and after the new prostheses. (Fig. 2)

Figure 1. The old dentures in occlusion.

Figure 2. The new dentures in occlusion.

Using the same cephalometric unit (ASACHI 3NCM F.M. Medident), standardized lateral cephalometric head films were taken, the first with the old dentures in place and the second with the new ones in place. (Figs. 3, 4). All head films were taken with the teeth in maximum intercuspation, coincident with the centric relation clinically assessed. The lateral cephalograms were digitized and analyzed using computer software (U BOX 4.3.F.M. Medident) and the results were double-checked by manually tracing and measuring.

Figure 3. The standardized lateral cephalometric head films with the old dentures in occlusion.

Figure 4. The standardized lateral cephalometric head films with the new dentures in occlusion.

RESULTS AND DISCUSSION

Table 1. Changes in cephalometric variables.

For the cephalometric analysis, we measured the parameters listed in Table 1, which enabled us to evaluate the changes in the vertical and sagittal maxillomandibular relationship, as well as some aspects regarding the facial profile.
All these cephalometric variables have been selected from Tweed (FMA angle, SNA angle, SNB angle, ANB angle), Steiner (SNA angle, SNB angle, SND angle, ANB angle, GoGn-SN angle), McNamara (A-N_|_FH distance, Pg-N_|_FH distance) and Ricketts (FH-NPg angle, NsaXi-XiPM angle, Ls-E line distance, Li-E line distance, A-NPg distance) analysis.

The cephalometric evaluation before the new prostheses. Teleradiographic characteristics with the old prostheses inserted on the residual ridges.
The lateral cephalometric head film analysis indicates a low angle skeletal pattern (FMA angle = 21°), with a high facial height index (FHI = 0.8) proving the clockwise mandibular rotation tendency. The relative sagittal intermaxillary discrepancy records as a negative value (ANB angle = -2°) because of the maxilla showing a retrognathic position to cranial base (SNA angle = 76°). The maxillary retrusion is objectively shown, besides the angular parameter from above, by a linear measurement taken over from Mc Namara analysis; this distance between A point and a perpendicular from nasion through the
Frankfurt horizontal plane is much lower than the normal value of 0 mm (A-N_|_FH distance = -7 mm). The reverse horizontal maxillomandibular relation is probably due to the specific resorption pattern of the two residual ridges (centripetal resorption in the maxilla and centrifugal resorption in the mandible) and to the tendency to forward displacement of the edentulous mandible (which turns a normal Class I maxillomandibular relation into a pseudo Class III relationship) as well. In addition, the close interaction between the horizontal and vertical planes makes the low angle pattern (the decrease of the mandible compass) to be horizontally translated by an increase of the reverse intermaxillary discrepancy. The general profile appearance is concave with the upper lip in a retrognathic position to esthetic line E (Ls-E line = -7 mm) and point A much more behind NPg line (A-NPg = -5.5 mm).
To synthetize, we can talk about a low angle retrusive skeletal pattern with a reverse intermaxillary discrepancy, clockwise mandibular rotation tendency and concave profile. It’s a specific picture for a complete denture wearer who suffered facial collapse and who’s appearance is improved not even by the increased, supraevaluated occlusal vertical dimension.10

The cephalometric evaluation with the new prostheses. Teleradiographic characteristics with the new prostheses inserted on the residual ridges.
After the placement of the new dentures, the vertical dimension was decreased: lower facial height angle changed from 52° to 49°, ANS - Me distance was decreased from 71 mm to 69 mm, the FMA angle decreased from 21° to 19°. As already mentioned above, the close interaction between the horizontal and vertical planes made this decrease of the occlusal vertical dimension to be horizontally expressed by an increase of the mandibular prognathism in relation to the cranial base, as determined from the facial depth angle (an increase from 88° to 89°), SNB (78° before, 79° after) and SND (77.5° before, 78.5° after) angles. The horizontal intermaxillary discrepancy was therefore increased from -2° to -3°.
The findings indicated that, as expected, there had been no significant change in the maxillary structures (SNA and BaNA angles maintained the same value after the new prostheses were inserted).
Conclusions: all the main determinates of vertical dimension used showed a decrease after the placement of the new dentures and this was in accordance with the clinical picture, because the new vertical dimension made all the old clinical symptoms to disappear.